JP3976741B2 - Transmission signal generating apparatus, radio base station, automatic gain control method, and radio signal transmission method - Google Patents

Description

  The present invention relates to a transmission signal generation device, a radio base station, an automatic gain control method, and a radio signal transmission method. About.

  Currently, mobile communication systems using radio signals are widespread. FIG. 14 is a block diagram showing a schematic configuration of the mobile communication system. As shown in FIG. 14, the mobile communication system provides various services to the user of the mobile terminal station 5 by the base station radio apparatus 1 performing radio communication with the mobile terminal station 5.

  The base station radio apparatus 1 includes a transmission signal generation apparatus that generates a transmission signal modulated according to a baseband signal, and a transmission amplification apparatus that transmits a radio signal according to the transmission signal.

  The transmission signal generation device includes, for example, a variable attenuator that adjusts the amplitude (level) of the transmission signal in order to prevent a change in input / output characteristics of the transmission signal generation device due to a change with time of a circuit in the transmission signal generation device Automatic gain control is performed to automatically adjust the gain.

  Specifically, the automatic gain control performed by the transmission signal generating device specifically detects the amplitude of the baseband signal and the transmission signal modulated based on the baseband signal and controlled in attenuation by the variable attenuator by the detector. In this control, the amplitude of the detection signal obtained at this time is compared by a comparator, and the attenuation amount of the variable attenuator is automatically adjusted based on the comparison result of the comparator.

  The detector that outputs the detection signal of the transmission signal includes a diode and a capacitor, and outputs a value obtained by averaging the transmission power value (level) of the transmission signal as the detection signal.

  On the other hand, services provided by mobile communication systems are diversified. For example, mobile communication systems provide not only voice-only services but also high-speed data communication services. Currently, a packet communication method is often used as a communication method used in high-speed communication.

  For example, in a base station radio apparatus of a CDMA (Code Division Multiple Access) type mobile communication system, when packet communication is performed, packet communication is performed by finely dividing data and varying the transmission rate according to the available line capacity. I do. In general, when the transmission rate is increased, it is necessary to increase the amplitude of the baseband signal in order to maintain communication quality. Therefore, when the base station radio apparatus performs packet communication, there is a possibility that the amplitude of the baseband signal changes abruptly.

  When the amplitude of the baseband signal changes abruptly, the transmission signal modulated according to the baseband signal becomes a burst-like signal (hereinafter referred to as “burst signal”) whose transmission power instantaneously increases or decreases. .

  Further, the base station radio apparatus increases the amplitude of the baseband signal when performing packet communication, and decreases the amplitude of the baseband signal when not performing packet communication. For this reason, a base station radio apparatus capable of performing packet communication may generate a burst signal (intermittent signal) in which the transmission power of the transmission signal increases or decreases as the transmission signal modulated according to the baseband signal. .

  Therefore, the radio base station apparatus corresponding to the high-speed communication data communication service transmits a burst signal while performing automatic gain control. In addition, when transmitting a voice, the radio base station apparatus transmits a voice signal (non-burst signal) at a constant transmission speed that is slower than the packet communication.

  Japanese Patent Laid-Open No. 5-315978 discloses an automatic gain control circuit that can perform a stable operation with respect to a burst signal input. Specifically, an input detection circuit for detecting the input signal (burst signal) to the variable attenuator, an output detection circuit for detecting the output signal (burst signal) of the variable attenuator, and detection for detecting the disconnection of the input signal And an automatic gain control circuit for fixing the attenuation amount of the variable attenuator to the attenuation amount immediately before the input signal is detected to be disconnected.

Patent Document 2 (Japanese Patent Laid-Open No. 11-205278) describes an OFDM (Orthogonal Frequency Division Multiplexing) demodulator that holds the control gain of an automatic gain control circuit when a burst signal is detected. Specifically, Patent Document 2 discloses an OFDM demodulator in which a control gain of an automatic gain control circuit is set using an AGC preamble signal transmitted before a burst signal.
JP-A-5-315978 Japanese Patent Laid-Open No. 11-205278

  When the base station radio apparatus can transmit a burst signal and a non-burst signal, the value (output level) of the detection signal output from the detector when the transmission signal is a burst signal is the transmission signal is a non-burst signal (for example, (Continuous signal) becomes smaller than the value (output level) of the detection signal output by the detector. This is because when detecting a burst signal, the detector detects when there is a signal in the transmission signal (for example, when a high-amplitude signal exists) and when there is no signal in the transmission signal (for example, This is because a value obtained by averaging the power of the transmission signal when the signal is off or when a low-amplitude signal is present is output.

  FIG. 15 shows the input / output characteristic 100 of the detector when the base station radio apparatus is performing burst transmission (transmitting a burst signal), and detection when the base station radio apparatus is continuously transmitting (transmitting a continuous signal). It is explanatory drawing which showed an example with the input-output characteristic 200 of a vessel. In FIG. 15, the horizontal axis x represents the transmission signal (dBm), and the vertical axis y represents the output of the detector (detection voltage (V)).

  As shown in FIG. 15, even when the same signal (hereinafter referred to as “predetermined signal”) is transmitted, the detection voltage detected by the detector when the predetermined signal is transmitted in bursts is the predetermined signal. Becomes smaller than the detection voltage detected by the detector when continuously transmitted.

  On the other hand, the amplitude of the baseband signal is detected for a portion where the signal exists in the transmission signal (for example, a signal portion having a high amplitude in the transmission signal).

  Therefore, in the base station radio apparatus that performs automatic gain control based on the amplitude of the baseband signal and the output of the detector, the output of the detector changes depending on whether or not the transmission signal is a burst signal. For example, if automatic gain control is set assuming that the transmission signal is a non-burst signal, the detector will falsely detect that the transmission signal is a burst signal, and automatic gain control will be accurate. The problem that it will not be made will arise.

  The automatic gain control circuit described in Patent Document 1 does not compare the baseband signal and the detection signal, but detects the detection signal of the input signal (burst signal) to the variable attenuator and the output signal (burst signal) of the variable attenuator. ) Detection signal. Since the automatic gain control circuit described in Patent Document 1 compares detection signals with each other, the detection error of the detector is canceled regardless of whether the transmission signal is a burst signal or a non-burst signal, and automatic gain control is performed. No malfunction will occur.

  However, the automatic gain control circuit described in Patent Document 1 requires an input detection circuit for detecting an input signal (burst signal) to the variable attenuator, which complicates the configuration.

  Further, the OFDM demodulator described in Patent Document 2 must use an AGC preamble signal for performing the control gain of the automatic gain control circuit. This necessitates a configuration for detecting the AGC preamble signal, which complicates the configuration.

  An object of the present invention is to provide a transmission signal generation device, a radio base station, an automatic gain control method, and a radio signal transmission method capable of preventing malfunction of automatic gain control with a simple configuration.

In order to achieve the above object, a transmission signal generation device of the present invention includes a baseband signal generation unit that generates a baseband signal, and a modulation signal corresponding to the baseband signal generated by the baseband signal generation unit. A modulation unit that outputs, a variable gain unit that adjusts a level of the modulation signal output from the modulation unit, and outputs a modulated signal with the adjusted level as a transmission signal; and a level of the transmission signal output from the variable gain unit And the variable gain unit so that the ratio of the level of the transmission signal detected by the detection unit and the level of the baseband signal generated by the baseband signal generation unit falls within a predetermined range. in the transmission signal generator and a control unit for controlling the gain, the control unit, the level of detected transmission signal by the detection unit base A comparison unit that outputs a comparison value according to a difference from the level of the baseband signal generated by the subband signal generation unit, and stores the comparison value output from the comparison unit, and the number of the comparison values The first comparison value that outputs the oldest comparison value among the accumulated comparison values is erased when the capacity exceeds its own capacity, and the accumulated comparison value is erased when the erase signal is input. A storage unit; a second storage unit that stores a comparison value output from the first storage unit; a comparison value stored in the first storage unit; and a comparison stored in the second storage unit When the average difference between each value exceeds a predetermined threshold value, it is determined that the transmission signal is a burst signal, and when the transmission signal is determined to be a burst signal, the variable gain unit And the erasure signal is stored in the first storage unit. And when it is determined that the transmission signal is not a burst signal, a controller that outputs the average of the comparison values stored in the second storage unit as a control signal for controlling the gain of the variable gain unit It is characterized by including these.

The automatic gain control method of the present invention includes a baseband signal generation step for generating a baseband signal, a modulation step for outputting a modulation signal corresponding to the baseband signal generated in the baseband signal generation step, and a variable step A gain unit adjusts the level of the modulation signal output in the modulation step and outputs a modulation signal whose level is adjusted as a transmission signal, and detects the level of the transmission signal output in the transmission signal output step The gain of the variable gain unit so that the ratio of the level of the transmission signal detected in the detection step and the level of the baseband signal generated in the baseband signal generation step falls within a predetermined range. an automatic gain control method and a control step of controlling, the control step, the detection stearate A comparison step for outputting a comparison value corresponding to a difference between the level of the transmission signal detected in the baseband and the level of the baseband signal generated in the baseband signal generation step, and the comparison value in the first storage unit When the number of comparison values exceeds the capacity of the first storage unit, the oldest comparison value among the comparison values stored in the first storage unit is output, In addition, when an erasing signal is input, a first storing step for erasing the comparison value accumulated in the first storage unit, and the comparison value output from the first storage unit are set to a second value. A second storage step for storing in the storage unit, and a difference between the average values of the comparison value stored in the first storage unit and the comparison value stored in the second storage unit is set to a predetermined threshold value. If it exceeds, it is determined that the transmission signal is a burst signal. When it is determined that the transmission signal is a burst signal, the gain of the variable gain unit is fixed and the erasure signal is output to the first storage unit, and when it is determined that the transmission signal is not a burst signal Includes a gain control step of outputting an average of the comparison values stored in the second storage unit as a control signal for controlling the gain of the variable gain unit .

  According to the above invention, it is determined whether the transmission signal is a burst signal based on the level of the transmission signal detected by the detection unit and the level of the baseband signal generated by the baseband signal generation unit, When it is determined that the transmission signal is a burst signal, the gain of the variable gain unit is fixed.

  Even if the transmission signal is a burst signal, according to the above invention, when the transmission signal is determined to be a burst signal, the gain of the variable gain unit is fixed, so the gain is controlled according to the burst signal. Thus, the abnormality of the gain of the variable gain section resulting from this can be reduced.

  Whether or not the transmission signal is a burst signal is determined based on the level of the transmission signal detected by the detection unit and the level of the baseband signal generated by the baseband signal generation unit. The level of the transmission signal detected by the detection unit and the level of the baseband signal generated by the baseband signal generation unit are information used when controlling the gain of the variable gain unit. For this reason, the information used when controlling the gain of the variable gain section can be used when determining whether or not the transmission signal is a burst signal, and the information can be shared.

  Further, the gain of the variable gain unit is controlled based on the level of the transmission signal detected by the detection unit and the level of the baseband signal generated by the baseband signal generation unit. Therefore, there is no need to use an input detection circuit for detecting an input signal (burst signal) to the variable gain device, and the configuration can be simplified. Further, since the AGC preamble signal for performing the control gain of the automatic gain control circuit is not used, it is not necessary to use the configuration for detecting the AGC preamble signal, and the configuration can be simplified.

Further, in the transmission signal generating apparatus, wherein the controller, when the transmission signal is determined to be burst signal, according to the comparison value the gain of the variable gain stored in the second storage unit It is desirable to fix this value.

In the automatic gain control method, when the gain control step determines that the transmission signal is a burst signal, the gain of the variable gain unit is set to a comparison value stored in the second storage unit. It is desirable to fix to the corresponding value.

  According to the above invention, when it is determined that the transmission signal is a burst signal, the gain of the variable gain unit is fixed to a value corresponding to the comparison value stored in the second storage unit.

  The comparison value stored in the second storage unit is output from the comparison unit before the transmission signal is determined to be a burst signal. The comparison unit outputs a comparison value corresponding to the difference between the level of the transmission signal detected by the detection unit and the level of the baseband signal generated by the baseband signal generation unit. For this reason, the gain of the variable gain section that is set when the transmission signal is determined to be a burst signal is set to a value corresponding to the comparison value output by the comparison section before the detector erroneously detects it. It is possible to prevent the influence of erroneous detection of the vessel.

  In the transmission signal generation device, it is preferable that the controller maintains the comparison value stored in the second storage unit when determining that the transmission signal is a burst signal.

  In the automatic gain control method, it is preferable that the gain control step maintains the comparison value stored in the second storage unit when it is determined that the transmission signal is a burst signal.

  According to the above invention, when it is determined that the transmission signal is a burst signal, the comparison value stored in the second storage unit is maintained. When the transmission signal is determined to be a burst signal, the comparison value stored in the second storage unit is output from the comparison unit before the transmission signal is determined to be a burst signal. . For this reason, it is possible to prevent the gain of the variable gain section that is set when the transmission signal is determined to be a burst signal from being affected by the erroneous detection of the detector.

The transmission signal generation apparatus further includes a temperature detection unit that detects an ambient temperature, and the comparison unit detects the level of the transmission signal detected by the detection unit according to the temperature detected by the temperature detection unit. It is preferable to output the comparison value according to the difference between the level of the transmission signal whose level is adjusted and the level of the baseband signal generated by the baseband signal generation unit.

The automatic gain control method further includes a temperature detection step of detecting an ambient temperature, and the comparison step includes a level of the transmission signal detected in the detection step according to the temperature detected in the temperature detection step. It is preferable to output the comparison value according to the difference between the level of the transmission signal whose level is adjusted and the level of the baseband signal generated by the baseband signal generation unit.

  According to the above invention, the level of the transmission signal detected by the detection unit is adjusted according to the temperature detected by the temperature detection unit, and the level of the transmission signal adjusted by the level is generated by the baseband signal generation unit. Whether or not the transmission signal is a burst signal is determined based on the level of the baseband signal.

  The level of the transmission signal detected by the detector may vary depending on, for example, the temperature characteristics of the variable gain section or the temperature characteristics of the detector. In the above invention, since the level of the transmission signal detected by the detection unit is adjusted according to the temperature detected by the temperature detection unit, the fluctuation of the level according to the temperature characteristic of the variable gain unit or the temperature characteristic of the detection unit Minutes can be corrected. Therefore, the accuracy of gain control of the variable gain unit can be improved.

  A radio base station according to the present invention includes the transmission signal generation device and a radio signal transmission unit that transmits a radio signal corresponding to the transmission signal output from the transmission signal generation device.

  The radio signal transmission method of the present invention includes the automatic gain control method and a radio signal transmission step of transmitting a radio signal corresponding to the transmission signal output in the transmission signal output step.

  According to the above invention, in the radio base station, it is possible to prevent malfunction of automatic gain control with a simple configuration.

  According to the present invention, it is determined whether or not the transmission signal is a burst signal based on the level of the transmission signal detected by the detection unit and the level of the baseband signal generated by the baseband signal generation unit. When it is determined that the signal is a burst signal, the gain of the variable gain unit is fixed.

  Even if the transmission signal is a burst signal, according to the above invention, when the transmission signal is determined to be a burst signal, the gain of the variable gain unit is fixed, so the gain is controlled according to the burst signal. Thus, the abnormality of the gain of the variable gain section resulting from this can be reduced.

  Whether or not the transmission signal is a burst signal is determined based on the level of the transmission signal detected by the detection unit and the level of the baseband signal generated by the baseband signal generation unit. The level of the transmission signal detected by the detection unit and the level of the baseband signal generated by the baseband signal generation unit are information used when controlling the gain of the variable gain unit. For this reason, the information used when controlling the gain of the variable gain section can be used when determining whether or not the transmission signal is a burst signal, and the information can be shared.

  Further, the gain of the variable gain unit is controlled based on the level of the transmission signal detected by the detection unit and the level of the baseband signal generated by the baseband signal generation unit. Therefore, there is no need to use an input detection circuit for detecting an input signal (burst signal) to the variable gain device, and the configuration can be simplified. Further, since the AGC preamble signal for performing the control gain of the automatic gain control circuit is not used, it is not necessary to use the configuration for detecting the AGC preamble signal, and the configuration can be simplified.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 is a block diagram showing a base station radio apparatus 1 as a radio base station according to an embodiment of the present invention.

  In FIG. 1, a base station radio apparatus 1 is a base station radio apparatus of a mobile communication system using a CDMA system, for example. The base station radio apparatus 1 includes a transmission signal generation apparatus 2, a transmission amplification apparatus 3, and an antenna 4.

  The transmission signal generation device 2 generates a baseband signal based on the transmission data S16 transmitted to the mobile terminal station 5, further generates a modulation signal corresponding to the generated baseband signal, and further generates the generated modulation signal. Amplify. The transmission signal generation device 2 outputs the amplified modulated signal as a transmission signal S5.

  The transmission amplification device 3 as a wireless signal transmission unit receives the transmission signal S5 and amplifies the transmission signal S5 to a power necessary for transmission. The transmission amplifying device 3 outputs the amplified transmission signal S5 to the antenna 4 as a transmission output S1, and causes the antenna 4 to transmit a radio signal corresponding to the transmission output S1.

  Note that the base station radio apparatus 1 shown in FIG. 1 shows only components necessary for downlink transmission. In addition to the configuration shown in FIG. 1, an actual base station radio apparatus 1 receives a radio signal from the mobile terminal station 5 and reproduces received data for each mobile terminal station 5 from the received signal. A signal processing unit that monitors a communication state of each station 5 and a radio that manages the position of each mobile terminal station 5 and relays communication between the mobile terminal station 5 and the network via a plurality of base station radio apparatuses 1 A communication interface device that is an interface with the network control device is provided.

  FIG. 2 is a block diagram showing the transmission signal generating apparatus 2 according to an embodiment of the present invention.

  In FIG. 2, the transmission signal generation device 2 includes a baseband unit 6 and an amplification unit 7. The baseband unit 6 includes a baseband signal generation unit 8, a modulation unit 9, a D / A unit 10, an A / D unit 15, a comparison control unit 16, and a D / A unit 17. The amplifying unit 7 includes a variable attenuator 11 as a variable gain unit, a filter 18, an amplifier 12, a coupler 13, and a detector 14.

  The baseband signal generator 8 generates a baseband signal S2 obtained by combining a plurality of transmission data S16 such as a pilot channel, a control channel, and a speech channel, and outputs the generated baseband signal S2. The baseband signal generator 8 generates baseband amplitude data S8 indicating the amplitude of the baseband signal S2, and outputs the generated baseband amplitude data S8. Note that the baseband signal generator 8 has the amplitude of the portion of the baseband signal S2 where the signal exists (for example, when the baseband signal S2 is a burst signal including a high amplitude signal and a low amplitude signal). Is output as baseband amplitude data S8.

  The modulation unit 9 receives the baseband signal S2 and outputs a modulation signal S3 modulated according to the baseband signal S2.

  The D / A unit 10 receives the modulated signal S3, performs digital-analog conversion on the modulated signal S3, and outputs the digital-analog converted modulated signal S3 as a radio signal S4.

  The variable attenuator 11 receives the radio signal S4 and varies the attenuation amount of the amplitude (level) of the radio signal S4 based on the control voltage S10 from the D / A unit 17. Furthermore, the gain of the variable attenuator 11 is controlled based on the control voltage S10 from the D / A unit 17.

  The filter 18 attenuates the interference wave component of the radio signal S4 whose signal level (amplitude) is adjusted by the variable attenuator 11.

  The amplifier 12 amplifies the level of the radio signal S4 in which the interference wave is attenuated by the filter 18 to the input level of the transmission amplifier 3, and outputs the amplified radio signal S4 as the transmission signal S5.

  The coupler 13 outputs the transmission signal S5 to the transmission amplification device 3 and the detector 14.

  The detector 14 receives the transmission signal S5 supplied from the coupler 13, detects the power (level) of the transmission signal S5 supplied from the coupler 13, and outputs a detection voltage S6 indicating the detected power. The detector 14 includes, for example, a diode and a capacitor, and outputs a value obtained by averaging the transmission power value (level) of the transmission signal S5 as the detection voltage S6.

  The A / D unit 15 receives the detection voltage S6, performs analog-digital conversion on the detection voltage S6, and outputs the detection voltage S6 obtained by analog-digital conversion as transmission power data S7.

  The comparison control unit 16 as a control unit controls the gain of the variable attenuator 11 so that the ratio between the transmission power data S7 and the baseband amplitude data S8 is within a predetermined range.

  Specifically, the comparison control unit 16 first converts each of the transmission power data S7 and the baseband amplitude data S8 into a power value. Thereafter, the comparison control unit 16 outputs a control signal S9 for making the respective data converted into the power value coincide.

  The D / A unit 17 receives the control signal S9, performs digital-analog conversion on the control signal S9, and outputs the digital-analog converted control signal S9 as the control voltage S10 to the variable attenuator 11. Therefore, the gain of the variable attenuator 11 is controlled by the comparison control unit 16.

  Further, the comparison control unit 16 determines whether or not the transmission signal S5 is a burst signal based on the transmission power data S7 and the baseband amplitude data S8. The comparison control unit 16 fixes the gain of the variable attenuator 11 when determining that the transmission signal S5 is a burst signal.

  FIG. 3 is a block diagram illustrating an example of the comparison control unit 16.

  In FIG. 3, the comparison control unit 16 includes a comparator 20, a memory A <b> 21, a memory B <b> 22, a controller 23, and a temperature sensor 24.

  The comparator 20 stores a baseband amplitude data conversion table and a transmission power data conversion table.

  FIG. 4 is an explanatory diagram showing an example of the baseband amplitude data conversion table. In FIG. 4, the baseband amplitude data conversion table 20a records baseband amplitude data 20a1 and a converted value (dBm) 20a2 as a power value in association with each other.

  FIG. 5 is an explanatory diagram showing an example of a transmission power data conversion table. In FIG. 5, the transmission power data conversion table 20b records the detection voltage (V) 20b1, the transmission power data 20b2, and the conversion value (dBm) 20b3 as a power value in association with each other.

  Returning to FIG. 3, the comparator 20 receives the transmission power data S7 and the baseband amplitude data S8 as inputs.

  When the transmission power data S7 is input, the comparator 20 converts the input transmission power data S7 into a conversion value associated with the value of the transmission power data S7 input in the transmission power data conversion table 20b. For example, when the value of the transmission power data S7 is “D”, the comparator 20 converts the transmission power data “D” into a power value of 40 dBm based on the transmission power data conversion table 20b.

  When the baseband amplitude data S8 is input, the comparator 20 associates the input baseband amplitude data S8 with the value of the baseband amplitude data S8 input in the baseband amplitude data conversion table 20a. Convert to converted value. For example, when the value of the baseband amplitude data S8 is “D”, the comparator 20 converts the baseband amplitude data “D” into a power value of 40 dBm based on the baseband amplitude data conversion table 20a.

  The comparator 20 outputs, as comparison data S11, a value obtained by subtracting the conversion value obtained by converting the transmission power data S7 from the conversion value obtained by converting the baseband amplitude data S8.

  The comparator 20 preferably corrects the transmission power data S7 based on the temperature data S15 supplied from the temperature sensor 24.

  The memory A21 as the first storage unit holds the comparison data S11 output from the comparator 20 for a predetermined period, and outputs the held comparison data S11 to the controller 23 as memory A data S12.

  Further, when the accumulation of the comparison data S11 exceeds the capacity of the memory A21, the memory A21 outputs the accumulated comparison data S11 to the memory B22 in the oldest order, and the comparison data S11 output to the memory B22 is recorded. New comparison data S11 is accumulated in the area.

  Further, when the erase signal S14 output from the controller 23 is input, the memory A21 erases the memory A data S12.

  The memory B22 as the second storage unit holds the comparison data S11 supplied from the memory A21, and outputs the held comparison data S11 to the controller 23 as memory B data S13.

  Further, when the storage of the comparison data S11 exceeds the capacity of the memory B22, the memory B22 discards the stored comparison data S11 in order of oldness.

  The memory B22 desirably has a larger capacity than the memory A21.

  FIG. 6 is an explanatory diagram showing an example of the memory A21 and the memory B22. In FIG. 6, the same components as those shown in FIG. 3 are denoted by the same reference numerals.

  In FIG. 6, the memory A <b> 21 has five storage areas indicated by numbers 1 to 5. The memory B22 has ten storage areas indicated by numbers 6 to 15. Note that the number of storage areas of the memory A21 is not limited to five and can be changed as appropriate. Further, the number of storage areas of the memory B22 is not limited to 10 and can be changed as appropriate.

  Returning to FIG. 3, the temperature sensor 24 monitors the temperature of the amplifying unit 7 and outputs temperature data S <b> 15 indicating the temperature of the amplifying unit 7 to the comparator 20.

  The controller 23 calculates an average value of each of the memory A data S12 and the memory B data S13.

  When the difference between the average value of the memory A data S12 and the average value of the memory B data S13 is within a predetermined threshold, the controller 23 determines that the transmission signal S5 is not a burst signal, and the memory B data S13. Is output to the D / A unit 17 as a control signal S9.

  When the difference between the average value of the memory A data S12 and the average value of the memory B data S13 is equal to or greater than a predetermined threshold value, the controller 23 determines that the transmission signal S5 is a burst signal and erases it in the memory A21. The signal S14 is output, and the comparison data S11 recorded in the memory A21 is erased.

By deleting the comparison data S11 recorded in the memory A21, the comparison data S11 is not supplied from the memory A21 to the memory B22, and the comparison data S11 recorded in the memory B22 is held. Controller 23, memory A when the difference between the average value and the average value of the memory B data S13 in data S12 is above the threshold a predetermined, D / A the average value of the memory B data S13 as the control signal S 9 To the unit 17.

  Next, an outline of the present embodiment will be described.

  The automatic gain control function performed by the base station radio apparatus 1 is such that the comparison controller 16 corrects the gain of the variable attenuator 11 in accordance with the aging and temperature change of the amplifier 12 and the filter 18, thereby This is a function for keeping the difference (ratio) from the output of the amplifier 7 within a certain range. Specifically, the comparison control unit 16 compares the baseband amplitude data S8 with the transmission power data S7 corresponding to the detection voltage S6 of the detection unit 14, and controls the gain of the variable attenuator 11 according to the comparison result. To do.

  When the base station radio apparatus 1 outputs a non-burst signal (for example, a transmission signal at the time of continuous transmission) as a transmission signal, the detection voltage S6 of the detector 14 is the baseband signal indicated by the baseband amplitude data S8. The value corresponds to the amplitude.

  Therefore, when the base station radio apparatus 1 outputs a non-burst signal as a transmission signal, the ratio between the baseband amplitude data S8 and the transmission power data S7 corresponding to the detection voltage S6 of the detection unit 14 is usually several tens, for example. Although a detection error (for example, a variation of about ± 0.3 dB) occurs within a detection time of about several hundred ms, it falls within a certain range.

  On the other hand, when the base station radio apparatus 1 outputs a burst signal as a transmission signal (for example, during packet communication), the detection voltage S6 of the detector 14 has the amplitude of the baseband signal indicated by the baseband amplitude data S8. It may not be the corresponding value. The reason is that the detector 14 has a power of a transmission signal when a signal is present in the transmission signal (when a high-amplitude signal is present) and a signal when the transmission signal is not present (when the signal is off or low-amplitude). This is because a value obtained by averaging the power of the transmission signal when the signal exists) is output.

  The fact that the detection voltage S6 of the detector 14 does not become a value corresponding to the amplitude of the baseband signal indicated by the baseband amplitude data S8 indicates that the detector 14 makes a false detection.

  Therefore, when the base station radio apparatus 1 outputs a burst signal as a transmission signal, the detector 14 is likely to be erroneously detected, and the automatic gain control does not function normally.

  In this embodiment, the comparison control unit 16 determines whether the baseband signal S2 or the transmission signal S5 is a burst signal. If the baseband signal S2 or the transmission signal S5 is a burst signal, the comparison control unit 16 Stop the automatic gain control function. For this reason, it is possible to prevent the automatic gain control from malfunctioning due to erroneous detection of the detector 14.

  When the baseband amplitude data S8 and the transmission power data S7 are input, the comparator 20 converts the values of the baseband amplitude data S8 and the transmission power data S7 using a conversion table, and the difference between the converted values. The comparison data S11 is calculated such that becomes zero, and the calculated comparison data S11 is output to the memory A21.

  The memory A21 accumulates a plurality of comparison data S11 for a certain period, and outputs the accumulated plurality of comparison data S11 to the controller 23 as memory A data S12.

  The memory B22 accumulates the plurality of comparison data S11 output from the memory A21 for a certain period, and outputs the accumulated plurality of comparison data S11 to the controller 23 as memory B data S13.

  The controller 23 calculates the average of each of the memory A data S12 and the memory B data S13, and determines that the baseband signal S2 and the transmission signal S5 are non-burst signals when the difference between the calculated averages is within the threshold value. The average value of the memory B data S13 is defined as a control signal S9. The D / A unit 17 D / A converts the control signal S9 output from the controller 23 and outputs the D / A converted control signal to the variable attenuator 11 as the control voltage S10.

  When the average difference between the memory A data S12 and the memory B data S13 is outside the threshold, the controller 23 determines that the baseband signal S2 and the transmission signal S5 are burst signals, and the memory B data S13. Is the control signal S9.

  When the baseband signal S2 and the transmission signal S5 are burst signals, an erroneous detection voltage S6 is output due to erroneous detection of the detector 14, and the digitally converted transmission power data S7 is erroneous.

  If the transmission power data S7 is incorrect, automatic gain control will malfunction if the gain of the variable attenuator 11 is fixed to a gain determined based on the incorrect transmission power data S7.

  In the present embodiment, when the controller 23 calculates the average of the memory A data S12 and the memory B data S13 and detects that the difference between the averages is outside the threshold value, the baseband signal S2 and the transmission signal It is determined that S5 is in a burst state (burst signal), and the comparison data S11 output by the comparator 20 while the burst signal is output is erased from the memory A21 using the erase signal S14. As a result, the comparison data S11 in the memory B22 is not updated to the comparison data S11 when the burst signal is generated, and the automatic gain control is stopped in a state where the comparison data S11 is held when the memory B data S13 is in the continuous signal transmission state. can do.

  Next, the operation will be described.

  Hereinafter, the operation when the transmission signal S5 from the base station radio apparatus 1 is a continuous signal and the operation when it is a burst signal (intermittent signal) will be described separately.

  First, the operation when the transmission signal S5 from the base station radio apparatus 1 is a continuous signal will be described.

  The baseband signal generation unit 8 inputs baseband amplitude data S8 representing the amplitude of the baseband signal S2 generated by the baseband signal generation unit 8 to the comparator 20 of the comparison control unit 16.

  The comparator 20 converts the baseband amplitude data S8 supplied from the baseband signal generator 8 into a power value based on the baseband amplitude data conversion table 20a.

  On the other hand, the detector 14 detects the power (level) of the transmission signal S5 generated by passing through the analog circuit of the variable attenuator 11, the filter 18 and the amplifier 12, and outputs the detected power as the detection voltage S6. .

  The A / D unit 15 performs analog-digital conversion on the detection voltage S6, and supplies the detection voltage S6 obtained by analog-digital conversion to the comparator 20 of the comparison control unit 16 as transmission power data S7.

  The comparator 20 converts the transmission power data S7 supplied from the A / D unit 15 into a power value based on the transmission power data conversion table 20b.

  The comparator 20 compares the power value converted from the baseband amplitude data S8 and the power value converted from the transmission power data S7, and outputs the difference between the compared power values as comparison data S11.

  For example, when the power value converted from the baseband amplitude data S8 is 40 dBm and the power value converted from the transmission power data S7 is 40 dBm, the comparator 20 outputs zero “0” as the comparison data S11. .

  For example, when the power value converted from the baseband amplitude data S8 is 40 dBm, the power value converted from the transmission power data S7 is 39 dBm (when transmission power data S7 = “E”). The comparator 20 outputs 1 dBm, which is the calculation result of (baseband amplitude data: 40 dBm) − (transmission power data: 39 dBm), as comparison data S11.

  The comparison data S11 output from the comparator 20 is stored in the memory A21. The comparison data S11 stored in the memory A21 is then transferred to the memory B22 and stored in the memory B22.

  In this embodiment, the comparison data S11 output from the comparator 20 is first stored in the storage area of number 1 in the memory A21.

  When the next comparison data S11 is input to the memory A21, the comparison data S11 stored in the number 1 storage area of the memory A21 is shifted to the number 2 storage area of the memory A21 and is input to the memory A21. Data S11 is stored in the storage area of number 1 in the memory A21. Thereafter, each time the comparison data S11 is input to the memory A21, the comparison data S11 is shifted to the storage area having a larger number in the memory A21.

  The comparison data S11 stored in the number 5 storage area of the memory A21 is shifted to the number 6 storage area of the memory B22 when the comparison data S11 is input to the memory A21. In the memory B22, every time the comparison data S11 is input to the memory A21, the comparison data S11 is shifted to the storage area having a larger number in the memory B22.

  Note that the comparison data S11 stored in the storage area number 15 in the memory B22 is discarded when the comparison data S11 is input to the memory A21.

  FIG. 7 is an explanatory diagram showing an accumulation example of the comparison data S11 in the memory A21 when the comparison data S11 is input to the memory A21 in the order of 00011-1-1000-11010.

  FIG. 8 is an explanatory diagram showing an accumulation example of the comparison data S11 in the memory B22 when the comparison data S11 is input to the memory A21 in the order of 00011-1-1000-11010.

  The memory A21 outputs data including all of the comparison data S11 stored therein to the controller 23 as memory A data S12. The controller 23 calculates an average value of the comparison data S11 included in the memory A data S12.

  Further, the memory B22 outputs data including all of the comparison data S11 stored therein to the controller 23 as memory B data S13. The controller 23 calculates an average value of the comparison data S11 included in the memory B data S13.

  The controller 23 calculates the difference between the average value of the memory A data S12 and the average value of the memory B data S13.

  For example, in the example shown in FIGS. 7 and 8, the average of the memory A data S12 is 0 (for example, rounded down), the average of the memory B data S13 is 0, and the difference between these is 0.

  If the threshold value for determining whether or not the transmission signal S5 is a burst signal is 2 dB in absolute value, the difference value 0 is within the threshold value, and therefore the controller 23 controls the transmission signal S5. Is determined to be a non-burst signal, and the average value 0 of the memory B data S13 is output as the control signal S9.

  Thereafter, the controller 23 newly takes in the new memory A data S12 and the new memory B data S13, and repeats the comparison determination operation based on the newly taken in memory A data S12 and memory B data S13.

  Next, the operation when the transmission signal S5 from the base station radio apparatus 1 is a burst signal will be described.

  Note that the transmission signal S5 of the base station radio apparatus 1 is a signal corresponding to continuous transmission, and the baseband amplitude data S8 and the transmission power data S7 are controlled in the vicinity of 40 dBm. From this state, the transmission signal S5 is Assume that the signal has shifted to a burst signal (burst signal).

  The baseband signal generator 8 inputs baseband amplitude data S8 representing the amplitude value of the baseband signal S2 to the comparator 20 of the comparison controller 16.

  For example, when the value of the baseband amplitude data S8 is “D”, the comparator 20 converts the baseband amplitude data “D” into a power value of 40 dBm based on the baseband conversion table 20a illustrated in FIG.

  On the other hand, since the signal input to the detector 14 is a burst signal, the detector 14 is shifted from the detection curve when the signal is a continuous transmission signal as shown in FIG. Resulting in.

  For example, in FIG. 15, when the detector 14 receives 40 dBm for continuous transmission, the detector 14 outputs 3.5 V as the detection voltage S6 (see X in FIG. 15). The A / D unit 15 performs analog-digital conversion on the detection voltage S6 (3.5 V), and outputs the detection voltage S6 (3.5 V) obtained by analog-digital conversion as transmission power data S7 (D). The comparator 20 converts the transmission power data S7 (D) into a power value of 40 dBm using the transmission power data conversion table 20a.

  However, when the detector 14 receives 40 dBm of the burst signal, the detector 14 erroneously detects and outputs 2V as the detection voltage S6. The A / D unit 15 performs analog-digital conversion on the detection voltage S6 (2V), and outputs the detection voltage S6 (2V) obtained by analog-digital conversion as transmission power data S7 (G). The comparator 20 converts the transmission power data S7 (G) into a power value of 37 dBm using the transmission power data conversion table 20a.

  The comparator 20 generates comparison data S11 of (baseband amplitude data: 40 dBm) − (transmission power data: 37 dBm) = 3 dB.

  FIG. 9 is an explanatory diagram showing an example of an accumulation state of the comparison data S11 in the memory A21 and the memory B22 when the comparator 20 outputs 3 dB as the comparison data S11. In FIG. 9, the same components as those shown in FIG.

  Note that the capacity of the memory A21 is determined so that the average of the memory A data S12 is not significantly affected even if the detection voltage S6 is detected by chance due to noise or the like and the transmission power data S7 temporarily increases. It is desirable. Further, it is desirable that the memory B22 has a sufficiently large capacity so that the average of the memory B data S13 is not significantly affected even if the detection voltage S6 is detected by chance. In this embodiment, the capacity of the memory A21 is 5, and the capacity of the memory B22 is 10.

  For example, when the burst signal continues five times and the average difference between the memory A data S12 and the memory B data S13 falls outside the threshold, the controller 23 outputs the erase signal S14 to the memory A21, and the memory The A data S12 is deleted.

  FIG. 10 is an explanatory diagram showing an example of a state in which the memory A data S12 is erased when the burst signal continues five times and the average difference between the memory A data S12 and the memory B data S13 is out of the threshold value. It is. In FIG. 10, the same components as those shown in FIG.

  In this embodiment, the comparison data S11 outside the threshold value, in other words, the comparison data S11 affected by the burst signal is deleted, so that the comparison data used to fix the gain (attenuation amount) of the variable attenuator 11 is deleted. As S11, the comparison data S11 affected by the burst signal is not used, and the control signal S9 can be fixed to a value not affected by the burst signal.

  The controller 23 erases the memory A data S12 by the erase signal S14, and then records the comparison data S11 output from the comparator 20 in the memory A21 again.

  When the control unit 23 records the comparison data S11 in the memory A21 again, as shown in FIG. 11, the burst signal is again repeated five times, and the average difference between the memory A data S12 and the memory B data S13. Is outside the threshold value, the controller 23 outputs the erase signal S14 again to erase the memory A data S12.

  When the control unit 23 records the comparison data S11 in the memory A21 again, as shown in FIG. 12, when the average difference between the memory A data S12 and the memory B data S13 is within the threshold value, When the comparison data S11 is output from the comparator 20, the controller 23 updates the comparison data S11 stored in the memory A21 and the comparison data S11 stored in the memory B22 one by one.

  In the present embodiment, when the transmission signal S5 is determined to be a burst signal, the gain of the variable attenuator 11 is fixed, so that the gain of the variable attenuator 11 is abnormal due to the false detection of the detector 14. Can be reduced.

  Whether or not the transmission signal is a burst signal is determined based on the level of the transmission signal S5 detected by the detection unit 14 and the level of the baseband signal generated by the baseband signal generation unit 8. . The level of the transmission signal detected by the detector 14 and the level of the baseband signal generated by the baseband signal generator 8 are information used when controlling the gain of the variable attenuator 11. For this reason, the information used when controlling the gain of the variable attenuating unit 11 can also be used when determining whether or not the transmission signal S5 is a burst signal, and the information can be shared.

  The gain of the variable attenuator 11 is controlled based on the level of the transmission signal S5 detected by the detector 14 and the level of the baseband signal generated by the baseband signal generator 8. For this reason, it is not necessary to use an input detection circuit for detecting an input signal (burst signal) to the variable attenuator 11, and the configuration can be simplified. Further, since the AGC preamble signal for performing the control gain of the automatic gain control circuit is not used, it is not necessary to use the configuration for detecting the AGC preamble signal, and the configuration can be simplified.

  Further, the comparison control unit 16 has a temperature sensor 24, the comparator 20 further has a temperature correction value conversion table 20c as shown in FIG. 15, and the comparator 20 is based on the temperature correction value conversion table 20c. The conversion value of the transmission power data S7 is adjusted according to the temperature detected by the temperature sensor 24, and the transmission signal S5 is burst based on the adjusted conversion value of the transmission power data S7 and the conversion value of the baseband amplitude data S8. You may make it determine whether it is a signal. In this case, it is possible to correct the change in the transmission power data S7 due to the temperature, and it is possible to improve the control accuracy of the controller 23.

  Further, by adjusting the conversion value of the transmission power data S7 according to the temperature detected by the temperature sensor 24, the temperature variation of the transmission power data S7 and the transmission power data S7 due to erroneous detection of the detector 14 by the burst signal. It becomes possible to distinguish fluctuations.

  For example, when the temperature sensor 24 has a temperature of the amplifying unit 7 of 45 ° C. and the gain of the amplifier 7 is −1 dB with respect to the design value, the transmission power data S7 also varies by −1 dB. At this time, even if a burst signal is transmitted as the transmission signal S5, for example, the conversion value of the baseband amplitude data S8 may be 40 dBm, and the conversion value of the transmission power data S7 may be 41 dBm. In this case, if the temperature correction is not executed, the comparison data S11 becomes 1 dB, and the controller 23 may erroneously determine that the transmission signal S5 is not a burst signal.

  On the other hand, when the comparison controller 16 performs temperature correction, a correction value −1 dB is obtained based on the temperature correction value conversion table 20c shown in FIG. 13, and the conversion value of the transmission power data S7 is the conversion value of the transmission power data S7. The value is corrected from 41 dBm to 42 dBm. Therefore, the comparison data S11 output from the comparator 20 is 2 dB, and when the threshold value for determining whether or not the signal is a burst signal is 1 dB, the controller 23 indicates that the detector 14 is erroneously detected. It becomes possible to determine the stability of the communication system by holding the automatic gain control value.

  In the embodiment described above, the illustrated configuration is merely an example, and the present invention is not limited to the configuration.

It is the block diagram which showed the wireless base station of one Example of this invention. It is the block diagram which showed the transmission signal generation apparatus of one Example of this invention. FIG. 3 is a block diagram illustrating an example of a comparison control unit illustrated in FIG. 2. It is explanatory drawing which showed an example of the baseband amplitude data conversion table. It is explanatory drawing which showed an example of the transmission power data conversion table. FIG. 4 is a block diagram illustrating an example of a memory A and a memory B illustrated in FIG. 3. 5 is an explanatory diagram showing an example of accumulation of comparison data by a memory A. FIG. 5 is an explanatory diagram showing an example of accumulation of comparison data by a memory B. FIG. 4 is an explanatory diagram showing an example of accumulation of comparison data by a memory A and a memory B. FIG. 4 is an explanatory diagram showing an example of accumulation of comparison data by a memory A and a memory B. FIG. 4 is an explanatory diagram showing an example of accumulation of comparison data by a memory A and a memory B. FIG. 4 is an explanatory diagram showing an example of accumulation of comparison data by a memory A and a memory B. FIG. It is explanatory drawing which showed an example of the temperature correction value conversion table. 1 is a block diagram showing a mobile communication system. It is explanatory drawing which showed the input / output characteristic of the detector.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Base station radio | wireless apparatus 2 Transmission signal generation apparatus 3 Transmission amplification apparatus 4 Antenna 5 Mobile terminal station 6 Baseband part 7 Amplification part 8 Baseband signal generation part 9 Modulation part 10 D / A part 11 Variable attenuator 12 Amplification part 13 Coupler 14 detector 15 A / D section 16 comparison control section 17 D / A section 18 filter 20 comparator 21 memory A
22 Memory B
23 Controller 24 Temperature sensor

Claims (10)

A baseband signal generator for generating a baseband signal;
A modulation unit that outputs a modulation signal corresponding to the baseband signal generated by the baseband signal generation unit;
A variable gain unit that adjusts the level of the modulation signal output from the modulation unit, and outputs the modulation signal adjusted in level as a transmission signal;
A detection unit for detecting a level of a transmission signal output from the variable gain unit;
A control unit that controls the gain of the variable gain unit so that the ratio between the level of the transmission signal detected by the detection unit and the level of the baseband signal generated by the baseband signal generation unit is within a predetermined range. In a transmission signal generation device including:
The controller is
A comparator that outputs a comparison value according to a difference between the level of the transmission signal detected by the detector and the level of the baseband signal generated by the baseband signal generator;
The comparison value output from the comparison unit is accumulated, and when the number of comparison values exceeds its own capacity, the oldest comparison value among the accumulated comparison values is output, A first storage unit for erasing the stored comparison value when an erasing signal is input;
A second storage for storing the comparison value output from the first storage;
When the difference between the average values of the comparison value stored in the first storage unit and the comparison value stored in the second storage unit exceeds a predetermined threshold, the transmission signal is a burst signal. When it is determined that the transmission signal is a burst signal, the gain of the variable gain unit is fixed and the erasure signal is output to the first storage unit, and the transmission signal is a burst signal. A controller that outputs an average of the comparison values stored in the second storage unit as a control signal for controlling the gain of the variable gain unit when it is determined that the transmission is not Signal generator. The transmission signal generation device according to claim 1,
Wherein the controller, the transmission signal when it is determined that the burst signal is to fix the gain of the variable gain to a value corresponding to the stored comparison value to said second storage unit, the transmission signal generation apparatus. The transmission signal generation device according to claim 2 ,
When the controller determines that the transmission signal is a burst signal, the controller maintains the comparison value stored in the second storage unit. The transmission signal device according to any one of claims 1 to 3 ,
It further includes a temperature detection unit that detects the ambient temperature,
The comparison unit adjusts the level of the transmission signal detected by the detection unit according to the temperature detected by the temperature detection unit, and is generated by the baseband signal generation unit and the level of the transmission signal adjusted in level. A transmission signal generation device that outputs the comparison value according to a difference from the level of the baseband signal. The transmission signal generation device according to any one of claims 1 to 4 ,
A radio base station, comprising: a radio signal transmission unit that transmits a radio signal according to a transmission signal output from the transmission signal generation device. A baseband signal generation step for generating a baseband signal;
A modulation step for outputting a modulation signal corresponding to the baseband signal generated in the baseband signal generation step;
A transmission signal output step in which the variable gain section adjusts the level of the modulation signal output in the modulation step and outputs the modulation signal adjusted in level as a transmission signal;
A detection step of detecting a level of the transmission signal output in the transmission signal output step;
Control step for controlling the gain of the variable gain unit so that the ratio between the level of the transmission signal detected in the detection step and the level of the baseband signal generated in the baseband signal generation step is within a predetermined range. In an automatic gain control method including:
The control step includes
A comparison step of outputting a comparison value according to a difference between the level of the transmission signal detected in the detection step and the level of the baseband signal generated in the baseband signal generation step;
The comparison value is accumulated in the first storage unit, and when the number of comparison values exceeds the capacity of the first storage unit, the comparison value accumulated in the first storage unit A first storage step of outputting the oldest comparison value among them and, if an erasure signal is inputted, erasing the comparison value accumulated in the first storage unit;
A second storage step of storing the comparison value output from the first storage unit in a second storage unit;
When the average difference between the comparison value stored in the first storage unit and the comparison value stored in the second storage unit exceeds a predetermined threshold, the transmission signal is a burst signal. When it is determined that the transmission signal is a burst signal, the gain of the variable gain unit is fixed and the erasure signal is output to the first storage unit. A gain control step of outputting an average of the comparison values stored in the second storage unit as a control signal for controlling the gain of the variable gain unit when it is determined that it is not Automatic gain control method. The automatic gain control method according to claim 6 ,
When the gain control step determines that the transmission signal is a burst signal, the gain of the variable gain unit is fixed to a value corresponding to the comparison value stored in the second storage unit. Control method. The automatic gain control method according to claim 7 ,
The automatic gain control method, wherein the gain control step maintains the comparison value stored in the second storage unit when the transmission signal is determined to be a burst signal. The automatic gain control method according to any one of claims 6 to 8 ,
A temperature detecting step for detecting an ambient temperature;
The comparison step adjusts the level of the transmission signal detected in the detection step according to the temperature detected in the temperature detection step, and is generated by the baseband signal generation unit and the level of the transmission signal adjusted in level. An automatic gain control method for outputting the comparison value according to the difference from the level of the baseband signal. All the steps included in the automatic gain control method according to any one of claims 6 to 9 ,
And a radio signal transmission step of transmitting a radio signal corresponding to the transmission signal output in the transmission signal output step.

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